Drying method and apparatus



April 4, 1939. QFFEN DRYING METHOD AND APPARATUS Filed Feb. 14, 1935 2Sheets-Sheet 2 BBQ/V420 OFFE/V ATTORNEY.

Patented Apr. 4, 1939 UNITED STATES PATENT OFFICE DRYING METHOD ANDAPPARATUS Bernard Offen, Chicago, Ill. Application February 14, 1935,Serial No. 6,453

provide apparatus which will efliciently and.eco-

nomically dry sheet materials and the like, and

which will effectively prevent the escape of gases.

and vapors emanating from said materials into the area surrounding theapparatus.

It is another object of the invention to provide means for supplyingconditioned or unconditioned air to a surface to be dried and means forwithdrawing said air after it has contacted said surface, whereby saidsurface will be dried and whereby gases and the like evaporated fromsaid surface will be exhausted with said withdrawn air.

It is another'object of the invention to provide a method of drying asurface in which the drying agent is introduced at a central point, iscaused to contact the surface to be dried, and is exhausted at aplurality of points on opposite sides of said central point.

It is another object of the invention to provide a drying hood in whichair is passed in contact with a surface to be dried, and is exhaustedafter it has contacted with said sur-.

face, and in which the static pressure of the air in the hood iscontrolled, whereby escape of said air from the hood will be prevented.

It is still another object of the invention to supply air to a movingsurface to be dried, and to exhaust said air .at a plurality of pointsalong the line of motion of said surface, whereby air passing to a firstof said exhaust points will have a first velocity relative to saidsurface and whereby air passing to a second of said exhaust points willhave a second velocity relative to said surface.

Still another object of the invention is to provide a method of drying asurface in which a volume of air is impinged against the surface at apoint of supply and is caused to be divided into a plurality of volumes,each of said volumes .-moving longitudinally of said surface, but indifferent directions and at different velocities relative to saidsurface.

A feature of the invention resides in the provision of a hood comprisinga-supply port, a

plurality of exhaust ports, and supply and ex-' surface to be dried, andmeans for controlling the amount of air supplied thereto, whereby thestatic pressure within the air passage may be regulated.

Another feature of the invention resides in the use of fibre bafiles todefine a plurality of air passages between the inlet and outlet ports ofthe hood.

Another feature of the invention resides in rotatably mounting thedrying hood whereby it may be readily removed from its normal operatingposition to facilitate inspection and repair.

. Still another feature of ,the invention resides in the provision ofmeans to prevent the building up of excessive pressures within the hood.

Other objects and features of the invention will become apparent fromthe following descrip tion, to be read in connection with theaccompanying drawings, in which:

Fig. 1 is a front elevational view of an illustrative form of theinvention showing the general assembly of applicants hood and the airsupply and exhaust connections to the hood;

Fig. 2 is a section taken on line 22 of Fig. 1, illustrating variousdetails of the hood construction and the application of'the invention tothe drying of a web;

Fig. 3 is a fragmentary section taken on the line 3-3 of Fig. 2,illustrating the baflle arrangement and the air seal; and

Fig. 4 is a view, taken similarly to that of Fig. 3, and'illustrating onan enlarged scale the structure of the baffles. I

Referring to the drawings, the numeral 5 designates generally a framestructure. Suitably mounted therein, as by the bearings i, are therollers I. A suitable number of these rollers, arranged as may bedesired, carry the web or sheet 8 which is to be dried, and which,during normal operation, moves upwardly as indicated by the arrows. Theinvention, though not limited thereto in its application, isparticularly well adapted ,to the drying of inked surfaces. Proximatethe web 8 is the drying hood, designated generally as 9. As illustrated,pipe III of the hood 9 is divided into a supply chamber II, and anexhaust chamber II, as by partition I3. Opening l4 admits air from thesupply chamber H to supply plenum [5. Adjustable louvres l6 permit airfrom plenum l5 to pass into contact with the web 8. Air is exhaustedthrough louvres Ila and Ill) and exhaust passages Na and H317, andpasses into exhaust chamber I2 through openings Na and l9b.

. A plurality of baffles 20 are spaced across the width of the hood andextend throughout the effective height of the hood contiguous to the web8, as shown in'Figs. 2 and 3. Thus, a plurality 'of air passages 2| areformed between adjacent baffles 2|), the hood 9, and the web 8. Airdischarged from supply louvres l6 impinges against the web 8- and passesto the exhaust louvres through the passages 2|, in contact with the web.

ill

It is well known that when any two substances of different material arebrought into intimate contact and then separated, they becomeelectrified. When paper or the like is carried on metallic rollers, theelectric charges developed are considerable. Therefore, to preventsparking where the baffles closely approach the web, applicantconstructs his baflies of non-conducting material, such as fibre or thelike.

In a preferred form of the invention, the supply louvres l6 are situatedbetweenexhaust jlouvres Ho and Nb. Thus, the air from the supply louvresI6 is divided, a part thereof flowing upwardly to louvres Na and a partthereof flowing downwardly to the louvres |'|b, through the passages 2|.To confine this air to the hood,

and to prevent its escape into the surrounding area, applicant providesan air seal and end baffles. As illustrated, the air seal comprises anangle piece 22 and a flange 23 extending from the frame at the ends'ofthe rollers I. When the hood 9 is in normal operating position, anglepiece 22 and flange 23 abut each other, as shown in Fig. 3, and thusprevent flow of air from or into the hood. At the top and bottom of thehood, end baffles 24 are provided. These baffles, as baffles 20, are ofelectrically non-conducting material. Their function is similar to thatof the air seal, but, obviously, they cannot completely seal the hoodarea from the surrounding area because of the necessity for clearancebetween the bafiies and the moving web.

It is important, however, that none of theplying to the passages 2|substantially at the center of the hood a quantity of air regulated bythe louvres l6, and by regulating the louvres Fla and Nb at the ends ofthe hood, applicant controls the air volumes and velocity of air in thepassages 2|. In this way, the static pressure within the air passagesnear the exhaust louvres may be determined, affording positive assurancethat exhaust air and fumes will not pass beyond the exhaust points butwill be confined to the hood and pass off through the exhaust duct 25.Thus, a pressure within the hood, adjacent the exhaust ports is producedand maintained less than that of the surrounding atmosphere. Leakage, ifany, will, therefore, be inward.

The air supplied to the hood- 9 by duct 26 may be room air or airconditioned to meet particular requirements. Moreover, applicant doesnot limit himself to any particular type of fan, blower or exhaustequipment, but contemplates that the invention be used in connectionwith such apparatus as may be suitable.

From time to time, it may be necessary or desirable to have access tothe web, the roller structure, or the working face of the hood.Accordingly, pipe I0 is rotatably mounted on rollers 21, carried onbrackets 28 of the frame structure 5. Stationary pipes 29, slidably fitwithin the inactive channels.

pipe I0 and provide communication between pipe l0 and the supply andexhaust ducts 26 and- 25.- Flange 30 and a'felt strip or the like 3|provide an air seal on the slip joint. Thus, the hood 9 may be readilyswung into the position indicated by the dot and dash lines of Fig. 2,

for inspection, adjustment or repair.

It is to be noted that the air passing to exhaust louvres |'|b travelsdownwardly, while the web 8 moves upwardly. Thus, when the web isfreshly wet, containing the largest amount of ink and applied material,the passage of the rection, the velocity of the air relative to thewebbeing less than it was during the first period of the drying operation.Thus, according to the invention, the drying effect of the air may begreatest when the web is wet, and less as there is less drying to bedone. adjustment of the louvres, the fan speed, and rapidity of travelof the web, uniform drying conditions may be produced and maintainedthroughout the hood. The shaded area on Fig. 2 denotes a sealed portionon the back end of the machine. The. hood itself seals the front end.

The supply opening may comprise a plurality of individual ports adaptedto feed separate streams of air to the various channels defined by thebaffles 20. Thus, for webs of different widths, the supply of air toseparate channels may be cut in and out, as desired. The bafliesthemselves may be made adjustable, so that when one or more channelsare'not in use, the baffles separating the active channel 'from theinactive ones may be raised to prevent escape of air to Thus, thebaflies 2|] may be formed of a main section 20w provided with a slot 2%formed therein and extending lengthwise of the baflle portion 200., anadjustable baf- 'fie portion 200 being slidably positioned within theslot or groove 20b. Thus, the portion 200 may be either completelyrecessed within the slot 20?), as when it is desired to providecommunication between the channels 2| on either side of the bafiie 20,or the portion 20c may be raised in any desired manner when it isdesired to prevent communication between the passages 2| on either sideof the baflle 20. The adjustment of the position of portion 200 may beeffected by manually grasping and manipulating this portion of thebaffle structure or may be accomplished in any other desired manner.

In order to relieve tension upon the web which may result at times, dueto building up of air pressure on the web, air breakers, such aselements 40, are provided. These may be narrow elements suitablypositioned between baffles 20 to break up the flow of air between thesupply and exhaust openings. Undesirable rush of air will thereby beprevented.

Though the invention has been described in connection with a moving web,many other applications of the invention will be apparent to thoseskilled in the art; since many modifications may be made in theinvention 'without departing from the scope and spirit thereof, it isintended that the foregoing description and the accompanying drawings beregarded as illustrative only, applicant limiting himself as indicatedin the appended claims.

However, by

I claim:

1. In drying equipment, a hood, an air supply port, and an exhaust portin said hood, a plurality of parallel channels formed on said hood,confining sides of said channels being formed of fibre bafiies, meansfor passing air through said supply port, means for passing said airthrough said channels, and means for exhausting said air through saidexhaust port, the material to be dried being positioned proximate thefree ends of said baiiles, whereby said material will be dried by theaction of air passing through said channels.

2. In drying equipment, a drying hood and means for passing air undersaid hood and in contact with the object to be dried, the edges of saidhood being proximate said object and being formed of an electricallynon-conductive material, whereby disruptive electrical discharge betweensaid material and said hood may be prevented.

3. In a system of the character described, a hood, a supply port, anexhaust port, means for conveying a web within the hood and past saidports to be dried by air supplied from the supply port and removedthrough the exhaust port, and means for relieving tension upon the webdue to the supply of air within the hood and its passage between saidports, said tension relieving means comprising a plurality of barsextending trans versely of the hood and being spaced therefrom and fromthe web, whereby air passing from said supply port to said exhaust portwill flow around said bars and be caused to eddy.

4. In a system of the character described, a hood, means for conveying aweb through the hood. an air supply. port, an air exhaust port, meansforming a plurality of adjacent air passages, said passage-forming meansincluding an adjustable baffle, means for circulating a plurality ofstreams of air through the hood in said air passages, and means forsupplying air to individual of the passages, said adjustable baflle beinadapted to segregate one of the component air streams from another.

5. In combination with means for guiding a paper web, a hood having apartition which divides said hood into an inner compartment and an outercompartment, said inner compartment being adjacent said guide means,said inner compartment having an outlet above the bottom thereof, saidouter compartment having an inlet below the bottom of said partition,means for' forcing air out of said outlet and for exhausting the airinto said inlet.

6. In combination with means for guiding a paper web, a turnably mountedpipe, a partition located within said pipe and dividing the same into aninlet compartment and into an outlet compartment, a hood connected tosaid pipe and turnable therewith, said hood having a hood partitionwhich divides it into an inner hood comand into said inlet and throughthe outer hoodcompartment and through the second pipe compartment.

7. Mechanism for drying a freshly printed paper web, comprising pressuremeans for creating a current of air and for directing said air currentalong the freshly printed surface of the web, and exhaust means separatefrom said pressure means for exhausting the air current after it hascontacted with said surface, said exhaust means having greater capacitythan said pressure means.

8. A method of drying a freshly printed paper web which consists inforcing a current of air along the freshly printed side of the web whilesubstantially confining said air current to said printed side, and thenexhausting the air current away from said Web, the rate of exhaustexceeding the rate of supply of air by said current.

9. In combination with means for guiding a web of paper, a pipe, apartition which divides said pipe intoa first pipe chamber, and a secondpipe chamber, a hood, a partition dividing said hood into a first hoodchamber and into a second hood chamber, said first hood chambercommunicating with said first pipe chamber, the second hood chambercommunicating with the second pipe chamber, means for supplying airunder pressure to the first pipe chamber, exhaust means connected to thesecond pipe chamber, said hood chambers being of unequal length, saidchambers having openings in the inner face of the wall of the hood whichis adjacent said guide means.

10. In combination with means for guiding a web of paper, a pipe, apartition which divides said pipe into a first pipe chamber and a secondpipe chamber, a hood, a partition dividing said hood into a first hoodchamber and into a second hood chamber, said first hood chamber comondhood chamber communicating with the second pipe chamber, means forsupplying air under pressure to the first pipe chamber, exhaust meansconnected to the second pipe chamber, said hood chambers being ofunequal lengith, said chambers having openings in the inner face of thewall of the hood which is adjacent said guide means, said pipe and hoodbeing. turnable in unison.

BERNARD OFZE'EN.

municating with said first pipe chamber, the sec- 60 DISCLAIMER2,152,770.-Bernamd Ofien, Chicago, Ill. DRYING METHOD AND APPARATUS.

dated April 4:, 1939. Disclaimer filed May 24, 1941, by the patentee.Hereby enters this disclaimer to claims 7 and 8 of said Letters Patent.

[Qflicial Gazette June 24, 1941 .1

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